Comparison of Coronary Computed Tomography Angiography,Fractional Flow Reserve,and Perfusion Imaging for Ischemia Diagnosis

Background

Fractional flow reserve (FFR) computation from coronary computed tomography angiography (CTA) datasets (FFR_CT) has emerged as a promising noninvasive test to assess hemodynamic severity of coronary artery disease (CAD), but has not yet been compared with traditional functional imaging.

Diagnostic value of 18F-FDG PET in the assessment of myocardial viability in coronary artery disease: A comparative study with 99mTc SPECT and echocardiography

ObjectiveTo investigate the diagnostic value of 18F-fluorodeoxyglucose positron emission tomography （18F-FDG PET） in the as-sessment of myocardial viability in patients with known coronary artery disease （CAD） when compared to99mTc single photon emission computed tomography （SPECT） and echocardiography, with invasive coronary angiography as the gold standard.MethodsThirty patients with diagnosed CAD met the selection criteria, with 10 of them （9 men, mean age 59.5 ± 10.5 years） undergoing all of these imaging proce-dures consisting of SPECT and PET, echocardiography and invasive angiography. Diagnostic sensitivity of these less invasive modalities for detection of myocardial viability was compared to invasive coronary angiography. Inter- and intra-observer agreement was assessed for di-agnostic performance of SPECT and PET.ResultsOf all patients with proven CAD, 50% had triple vessel disease. Diagnostic sensitivity of SPECT, PET and echocardiography was 90%, 100% and 80% at patient-based assessment, respectively. Excellent agreement was achieved between inter-observer and intra-observer agreement of the diagnostic value of SPECT and PET in myocardial viability （k= 0.9）. Conclusion18F-FDG PET has high diagnostic value in the assessment of myocardial viability in patients with known CAD when com-pared to SPECT and echocardiography. Further studies based on a large cohort with incorporation of18F-FDG PET into patient management are warranted.     

Characteristics of patients with abnormal stress technetium Tc 99m sestamibi SPECT studies without significant coronary artery diameter stenoses

BACKGROUND: Single-photon emission computed tomography (SPECT) sestamibi (MIBI) is an excellent tool for detection of coronary artery disease (CAD), preoperative risk assessment, and follow-up management after coronary revascularization. While the sensitivity of MIBI SPECT for detecting CAD has been reported to exceed 90%, the specificity ranges between 53-100%. HYPOTHESIS: The study was undertaken to assess characteristics of patients with abnormal stress technetium Tc99m sestamibi SPECT (MIBI) studies without significant coronary artery diameter stenoses (< 50%). METHODS: Between January 1999 and November 2000, 270 consecutive patients were referred for coronary angiography due to reversible MIBI uptake defects during exercise. In 41 patients (15%; 39% women, mean age 59 +/- 9 years), reversible MIBI uptake defects were assessed although coronary angiography showed no significant CAD. These patients were compared with age- and gender-matched patients with perfusion abnormalities (39% women, mean age 60 +/- 9 years), due to significant CAD (coronary artery stenosis > 50%). RESULTS: There were no significant differences between the two groups regarding body mass index, left bundle-branch block (LBBB), or method of stress test (dipyridamole in patients with LBBB or physical inactivity [n = 11] and exercise in all the others [n = 30]). Left ventricular hypertrophy (44 vs. 23%, p = 0.05) and left anterior fascicular block (LAFB) (17 vs. 0%, p = 0.005) were more common in patients with perfusion abnormalities with no significant CAD, whereas ST-segment depression during exercise (17 vs. 37% p = 0.05) and angina during exercise (15 vs. 29%, p = 0.02) were significantly less common than in patients with abnormal MIBI perfusion studies and angiographically significant CAD. Sestamibi uptake defects during exercise were significantly smaller in patients without significant CAD than in matched controls with significant CAD (p < 0.0004). CONCLUSION: Of 270 consecutive patients, 41 (15%) referred to coronary angiography due to reversible MIBI uptake defects showed coronary artery stenoses < 50%. Twenty-six (10%) of these presented angiographically normal coronary arteries. The significantly higher proportion of left ventricular hypertrophy and LAFB in patients with reversible MIBI uptake defects without significant CAD suggest microvascular disease, angiographically underestimated CAD, and conduction abnormalities as underlying mechanisms.     

Metabolic imaging using F18-fluorodeoxyglucose to assess myocardial viability

Over the past 10 years, F18-fluorodeoxyglucose (FDG) imaging with positron emission tomography (PET) has emerged as an important technique in the delineation of myocardial viability. Using this technique it has become possible to predict recovery of ventricular function after revascularization in patients with chronic coronary artery disease. Data from long-term (although retrospective) follow-up studies have demonstrated that patients with viable myocardium on FDG PET who do not undergo revascularization are prone to cardiac events, including cardiac death and non-fatal infarction. The same studies have pointed out that patients with viable tissue on FDG PET, who do undergo revascularization, improve substantially in symptoms related to congestive heart failure. To allow FDG imaging in centers without PET equipment, recent studies have evaluated the use of FDG imaging with single photon emission computed tomography (SPECT) and 511 keV collimators. Preliminary data using this alternative approach are promising, but need further confirmation. In this review the experience with FDG imaging (using either PET or SPECT) in the assessment of tissue viability in patients with coronary artery disease will be discussed.     

13N-NH3PET腺苷负荷—静息心肌灌注显像在冠状动脉病变功能学评价中的应用价值

目的探讨13N-NH3PET腺苷负荷—静息心肌灌注显像（MPI）在疑诊或确诊冠心病患者冠脉病变功能学评价中的应用价值。方法 30例疑似或确诊的冠心病患者,均接受13N-NH3PET腺苷负荷—静息MPI和冠状动脉造影（CAG）检查。结果用13N-NH3PET腺苷负荷—静息MPI评估30例患者197个冠状动脉节段供血区,结果50个节段供血区确定为存活心肌（24个节段供血区发现可逆性灌注缺损,26个节段供血区呈固定性灌注缺损）,3个节段供血区确定为无存活心肌,其余144个节段供血区为正常心肌。以CAG发现≥50%狭窄为CAG检查结果阳性标准,30例中MPI与CAG结果相符合者24例。阳性22例、假阳性5例、假阴性1例、阴性2例。敏感度95.65%、特异度28.57%、阳性预测值81.48%、阴性预测值66.67%。以CAG发现≥75%狭窄为CAG阳性标准,30例中MPI结果与CAG结果相符合者25例。其中阳性22例、假阳性5例、假阴性0例、阴性3例。敏感度为100%、特异度为37.5%、阳性预测值为81.48%、阴性预测值为100%。结论 MPI用于疑似或确诊冠心病患者冠状动脉功能学评价效果较好。     

腺苷负荷心肌灌注显像评价中年女性心肌供血异常的临床价值

目的:评价国产腺苷负荷99Tcm-MIBI心肌灌注显像对65岁以下的中年女性患者心肌供血异常的判断临床价值。方法:2007年1月至2008年7月临床怀疑冠心病的中年女性109例,年龄40～65岁,平均年龄(54.9±6.1)岁,所有患者均在1个月内施行常规2d法腺苷负荷-静息心肌灌注显像(MPI)和冠状动脉造影术(CAG)检查。MPI和CAG图像由2名以上核医学/放射科医师共同读片;MPI评价标准:供血区某一心肌节段负荷时,出现放射性稀疏或缺损,静息时消失或改善,判定为心肌缺血;如静息时仍为放射性缺损,判定为心肌梗死。CAG评价标准:3支主要冠状动脉血管中至少有1支主要冠状动脉管径狭窄≥50%,判定为阳性。MPI与CAG对照,评价腺苷MPI对冠心病的诊断效能(敏感性、特异性和准确性)。结果:109例受检者中,MPI显示:阴性62例,阳性47例,心肌缺血42例,心肌梗死5例;累及59个室壁段,其中前降支供血区32段,回旋支供血区12段,右冠状动脉供血区15段。CAG显示:冠状动脉正常72例,冠状动脉异常37例,其中单支病变23例,双支病变7例,3支病变7例;冠状动脉异常37例中核素心肌灌注显像阳性31例,阴性6例;冠状动脉正常72例中核素心肌灌注显像56例阴性,16例阳性。腺苷负荷MPI对65岁以下女性患者诊断冠心病的灵敏度为83.8%(31/37例),特异性为77.8%(56/72例),准确性为79.8%(87/109例),阳性预测值为65.9%(31/47例),阴性预测值为90.3%(56/62例)。结论:腺苷负荷心肌灌注显像用于中年女性冠心病的诊断有较高的诊断效能,具有较高的临床应用价值。可作为中年女性早期诊断冠心病在运动心电图之外有效的、优先考虑的选择。     

Culprit lesion and jeopardized myocardium: Correlation between coronary angiography and single-photon emission computed tomography

Background: The term “culprit lesion” is used to designate the coronary stenosis responsible for the symptoms of the patient with coronary artery disease. Its detection is essential when partial revascularization is contemplated. The term “jeopardized myocardium” is commonly used to mean the amount of myocardium put in danger by all the stenotic lesions; however, it should be restricted to the amount of myocardium that could become infarcted if only the most severe stenoses were occluded. Hypothesis: The aim of this study was to investigate (1) the agreement between coronary myocardial single-photon emission computed tomography (SPECT) and coronary angiography for the identification of the culprit lesion, and (2) the correlation of the two studies in the quantification of jeopardized myocardium. Methods: In all, 159 patients with coronary artery disease without previous myocardial infarction were included in the study. A score for myocardial SPECT was correlated with the angiographic scores by Califf and Gensini and with the authors' score which includes adjustment for collateral circulation. Results: The agreement between coronary angiography and SPECT for the diagnosis of the culprit lesion was 84% (87/104). The correlations between the scores of angiography and SPECT to assess jeopardized myocardium when all coronary stenoses were taken into account were significant (p<0.0001), but their coefficients were suboptimal (r = 0.48 for Califf, r = 0.48 for Gensini, and r = 0.65 for the authors' score). When only the jeopardized myocardium resulting from the culprit lesion was considered, the correlation clearly improved (r=0.85). Conclusion: Thus, in 84% of patients with multivessel disease, an agreement between coronary angiography and myocardial SPECT for the diagnosis of the culprit lesion was observed. The correlation between these techniques for the quantification of jeopardized myocardium from the culprit lesion was satisfactory.     

Diagnostic Value of Transluminal Attenuation Gradient for the Presence of Ischemia as Defined by Fractional Flow Reserve and Quantitative Positron Emission Tomography

Objectives

The aim of this study was to investigate the incremental diagnostic value of transluminal attenuation gradient (TAG), TAG with corrected contrast opacification (TAG-CCO), and transluminal diameter gradient (TDG) over coronary computed tomography angiography (CTA)–derived diameter stenosis alone for the identification of ischemia as defined by both the invasive reference standard fractional flow reserve (FFR) and the noninvasive reference standard quantitative positron emission tomography (PET).

Incremental Diagnostic Value of Stress Computed Tomography Myocardial Perfusion With Whole-Heart Coverage CT Scanner in Intermediate- to High-Risk Symptomatic Patients Suspected of Coronary Artery Disease

Objectives

The goal of this study was to evaluate the diagnostic accuracy of stress computed tomography myocardial perfusion (CTP) for the detection of functionally significant coronary artery disease (CAD) by using invasive coronary angiography (ICA) plus invasive fractional flow reserve (FFR) as the reference standard in consecutive intermediate- to high-risk symptomatic patients.

Myocardial perfusion imaging and cardiac events in a cohort of asymptomatic patients with diabetes living in southern France.

AIMS: To assess the association between abnormal stress myocardial perfusion imaging (MPI) and cardiac events (CE) in asymptomatic patients with diabetes and with > or = 1 additional risk factor. Predictors of abnormal stress MPI were also evaluated. METHODS: Four hundred and forty-seven consecutive patients who underwent stress MPI were prospectively followed for 2.1 [0.5-4.1] years for the subsequent occurrence of hard CE (myocardial infarction and sudden or coronary death) and soft CE (unstable angina and ischaemic heart failure requiring hospitalization). Re-vascularization procedures performed as a result of the screening protocol were not included in the analysis. RESULTS: Follow-up was successful in 419 of 447 patients (94%), of whom 71 had abnormal MPI at baseline. Medical therapy was intensified in all subjects and especially in those with abnormal MPI. Twenty-three patients with abnormal MPI underwent a re-vascularization procedure. CEs occurred in 14 patients, including six of 71 patients (8.5%) with abnormal MPI and eight of 348 patients (2.3%) with normal MPI (P < 0.005). Only two patients developed a hard CE and 12 a soft CE. In multivariate analysis, abnormal MPI was the strongest predictor for CEs [odds ratio (OR) (95% CI) = 5.6 (1.7-18.5)]. Low-density lipoprotein cholesterol > or = 3.35 mmol/l [OR (95% CI) = 7.3; 1.5-34.7] and age > median [OR (95% CI) = 6.0 (1.2-28.6)] were additional independent predictors for CE. The independent predictors for abnormal MPI were male gender, plasma triglycerides > or = 1.70 mmol/l, creatinine clearance < 60 ml/min and HbA1c > 8%, with male gender the strongest [OR (95% CI) = 4.0 (1.8-8.8)]. CONCLUSIONS: Asymptomatic patients with diabetes in this study had a very low hard cardiac event rate over an intermediate period. This could be explained by the effects of intervention or by the low event rate in the background population. Randomized studies of cardiac heart disease screening are required in asymptomatic subjects with diabetes to determine the effectiveness of this intervention.     

Second-Line Myocardial Perfusion Imaging to Detect Obstructive Stenosis: Head-to-Head Comparison of CMR and PET

BackgroundGuidelines recommend verification of myocardial ischemia by selective second-line myocardial perfusion imaging (MPI) following a coronary computed tomography angiography (CTA) with suspected obstructive coronary artery disease (CAD). Head-to-head data on the diagnostic performance of different MPI modalities in this setting are sparse.ObjectivesThe authors sought to compare, head-to-head, the diagnostic performance of selective MPI by 3.0-T cardiac magnetic resonance (CMR) and ⁸²rubidium positron emission tomography (RbPET) in patients with suspected obstructive stenosis at coronary CTA using invasive coronary angiography (ICA) with fractional flow reserve (FFR) as reference.MethodsConsecutive patients (n = 1,732, mean age: 59.1 ± 9.5 years, 57.2% men) referred for coronary CTA with symptoms suggestive of obstructive CAD were included. Patients with suspected stenosis were referred for both CMR and RbPET and subsequently ICA. Obstructive CAD was defined as FFR ≤0.80 or >90% diameter stenosis by visual assessment.ResultsIn total, 445 patients had suspected stenosis on coronary CTA. Of these, 372 patients completed both CMR, RbPET and subsequent ICA with FFR. Hemodynamically obstructive CAD was identified in 164 of 372 (44.1%) patients. Sensitivities for CMR and RbPET were 59% (95% CI: 51%-67%) and 64% (95% CI: 56%-71%); P = 0.21, respectively, and specificities 84% (95% CI: 78%-89%) and 89% (95% CI: 84%-93%]); P = 0.08, respectively. Overall accuracy was higher for RbPET compared with CMR (73% vs 78%; P = 0.03).ConclusionsIn patients with suspected obstructive stenosis at coronary CTA, CMR, and RbPET show similar and moderate sensitivities but high specificities compared with ICA with FFR. This patient group represents a diagnostic challenge with frequent mismatch between advanced MPI tests and invasive measurements. (Danish Study of Non-Invasive Diagnostic Testing in Coronary Artery Disease 2 [Dan-NICAD 2]; NCT03481712)     

Women with high exercise tolerance and the role of myocardial perfusion imaging

BACKGROUND: Myocardial perfusion imaging (MPI) provides incremental diagnostic and prognostic information, even in patients with high exercise tolerance. HYPOTHESIS: Myocardial perfusion imaging provides significant diagnostic value, specifically in women with high exercise tolerance. METHODS: Our study population consisted of all women who underwent exercise MPI in our Department from January 1992 to June 1996 and reached at least Stage IV in the Bruce protocol. Patients were divided into those with known and those with possible coronary artery disease (CAD). All patients were followed for 3 years from the performance of MPI. RESULTS: Of 4,803 women who underwent myocardial perfusion imaging, 3,183 had exercise stressing, and of those, 311 reached at least Stage IV in the Bruce protocol. Of these 311 MPI scans, only 23 (7.4%) were abnormal (reversible, fixed, or mixed) and the remaining 288 (92.6%) were normal. Of the 82 patients with known CAD, 13 (15.8%) had an abnormal MPI, while only 10 (4.4%) of the 229 patients with possible CAD. No myocardial infarction or cardiac death occurred within 3 years; one patient with normal MPI needed revascularization. CONCLUSION: In women with high exercise tolerance, especially in those without already known CAD, the yield of MPI is very low. Women with high exercise tolerance have an excellent prognosis.     

Prospective Comparison of FFR Derived From Coronary CT Angiography With SPECT Perfusion Imaging in Stable Coronary Artery Disease: The ReASSESS Study

Objectives

This study sought to compare the per-patient diagnostic performance of coronary computed tomography angiography (CTA)-derived fractional flow reserve (FFR_CT) with that of single-photon emission computed tomography (SPECT), using a fractional flow reserve (FFR) value of ≤0.80 as the reference for diagnosing at least 1 hemodynamically significant stenosis in a head-to-head comparison of patients with intermediate coronary stenosis as determined by coronary CTA.

Multimodality imaging in coronary artery disease – “The more the better?”

Multimodality imaging in coronary artery disease (CAD) comprises a combination of information from more than one imaging technique. These combinations, performed in a side-by-side or fusion mode, include computed tomography (CT) and single photon emission computed tomography (SPECT), positron emission tomography (PET) and CT, and PET with magnetic resonance imaging (MRI). Data thus obtained lead to either a summative or synergistic gain of information. For instance, morphology (coronary plaques/stenosis) can be depicted by coronary CT angiography, whereas functional aspects of CAD such as myocardial perfusion abnormalities or myocardial metabolism can be evaluated by the complementary technique in order to separate a hemodynamic significant coronary stenosis from a hemodynamic non-significant stenosis. Distinguishing these two entities has an important impact on patient management. Beyond the diagnostic yield, some of these combinations in multimodality imaging also have prognostic implications. In this article, we will describe different multimodality imaging approaches (CT/SPECT, PET/CT and PET/MRI) for evaluation of CAD in patients with suspected or known CAD and put them into the context of current knowledge.     

MR-IMPACT: comparison of perfusion-cardiac magnetic resonance with single-photon emission computed tomography for the detection of coronary artery disease in a multicentre, multivendor, randomized trial.

AIMS: To determine in a multicentre, multivendor trial the diagnostic performance for perfusion-cardiac magnetic resonance (perfusion-CMR) in comparison with coronary X-ray angiography (CXA) and single-photon emission computed tomography (SPECT). METHODS AND RESULTS: Of 241 eligible patients from 18 centres, 234 were randomly dosed with 0.01, 0.025, 0.05, 0.075, or 0.1 mmol/kg Gd-DTPA-BMA (Omniscantrade mark, GE-Healthcare) per stress (0.42 mg/kg adenosine) and rest perfusion study. Coronary artery disease (CAD) was defined as diameter stenosis > or =50% on quantitative CXA. Five CMR and eight SPECT studies (of 225 complete studies) were excluded from analyses due to inadequate quality (three blinded readers scored per modality). The comparison of CMR vs. SPECT was based on receiver operating characteristic (ROC) analysis. Perfusion-CMR at the optimal CM dose (0.1 mmol/kg) had similar performance as SPECT, if only the SPECT studies of the 42 patients with this dose were considered [area under ROC curve (AUC): 0.86 +/- 0.06 vs. 0.75 +/- 0.09 for SPECT, P = 0.12]; however, diagnostic performance of perfusion-CMR was better vs. the entire SPECT population (AUC: 0.67 +/- 0.05, n = 212, P = 0.013). CONCLUSIONS: In this multicentre, multivendor trial, ROC analyses suggest perfusion-CMR as a valuable alternative to SPECT for CAD detection showing equal performance in the head-to-head comparison. Comparing perfusion-CMR with the entire SPECT population suggests CMR superiority over SPECT, which warrants further evaluation in larger trials.     

腺苷负荷心肌灌注显像正常女性中心电图呈缺血改变35例分析

目的:探讨腺苷负荷心电图(ECG)呈缺血性改变而核素心肌灌注显像(MPI)正常的女性患者,MPI和冠状动脉CT(CTCA)结果对冠心病(CAD)诊断的临床价值。方法:回顾性分析2008年5月至2011年11月疑诊冠心病行腺苷负荷/静息MPI的4 142例女性患者资料,将其中35例〔年龄39～76岁,平均年龄(55.74±9.43)岁〕腺苷负荷ECG呈缺血改变,但MPI正常者作为研究对象,35例患者均利用SPECT/CT行MPI和同机CTCA检查,其中1例患者在1个月内行冠状动脉造影(CAG)检查。结果:35例患者静息状态ECG均正常,腺苷负荷ECG则出现ST段水平或下斜型下移≥0.1 mV,停止负荷1 min后ECG恢复正常,提示心肌缺血改变,随后的负荷/静息MPI均未见心肌缺血改变。同机CTCA结果示:27例冠状动脉正常(27/35,77.1%),7例冠状动脉粥样硬化性改变(7/35,20.0%),1例(2.9%)为3支冠状动脉狭窄性病变,程度均≥50%,其CAG显示:LAD近段狭窄75%,LCX中段狭窄90%,RCA近中段狭窄95%。结果提示:此组患者中97.1%的冠状动脉是正常或仅呈硬化性改变,而无心肌缺血存在。结论:女性患者易出现负荷ECG"假阳性";负荷MPI是评价此类患者有无冠心病的重要手段;同机CTCA则是避免冠状动脉3支病变而MPI"假阴性"的弥补手段,因此,利用SPECT/CT施行同机MPI/CTCA是对此类患者进行冠心病筛查的准确性较高的无创性评价手段。     

Characteristics and outcome of octogenarian population referred for myocardial perfusion imaging: comparison with non-octogenarian population with reference to gender

BACKGROUND: Octogenarian patients referred for stress myocardial perfusion imaging (MPI) differ from younger (non-octogenarian) patients in that they have lower prevalence of risk factors for CAD, but more frequent ischemic events and higher cardiac mortality. HYPOTHESIS: The purpose of this study was to investigate the efficacy of MPI in octogenarian men and women compared with that in the younger population, and to compare the prognostic value of stress MPI in both populations. METHODS: We studied 162 consecutive patients aged > or = 80 years who were referred for stress MPI, and compared them with 253 consecutive patients aged < 80 years. Patients completed a questionnaire encompassing information about the existence of coronary risk factors, cardiac symptoms, coronary artery disease (CAD), myocardial infarction, coronary artery bypass graft, percutaneous transluminal coronary angioplasty, and results of stress MPI. The patients were followed up for cardiac mortality for a mean of 45 +/- 12 months. RESULTS: There were 61 women and 101 men (17% of all referrals) with a mean age of 83 +/- 3 (range 80-90). Parameters of octogenarian patients demonstrated a significantly lower prevalence of non-insulin-dependent diabetes mellitus (p < 0.02), hypercholestrolemia (p < 0.001), and smoking (p = 0.001) compared with non-octogenarian patients. The prevalence of known CAD was similar, but the prevalence of abnormal resting electrocardiogram, left ventricular (LV) dilatation, and stress-induced ischemia was significantly higher in octogenarians (p < 0.002). Cardiac mortality rate per year was 4.3% in octogenarians versus 1.3% in the younger population (p < 0.0001). The independent predictors according to MPI of cardiac death were LV dilatation and presence of ischemia in octogenarians, and severity of ischemia in non-octogenarians. CONCLUSIONS: The octogenarian population referred for stress single-photon emission computed tomography differed from the non-octogenarian group in that it had a lower prevalence of risk factors for CAD, but more frequent ischemic events and higher cardiac mortality; however, MPI variables predict adverse outcome in both populations.     

Myocardial perfusion imaging in coronary artery disease

Radionuclide myocardial perfusion imaging (MPI) can be used to demonstrate the presence of coronary heart disease and to risk stratify and guide management of patients with known disease. It has the ability to localize hemodynamically important coronary stenoses, and assess the extent and severity of coronary obstruction by the presence and extent of perfusion defects. A normal stress MPI indicates the absence of coronary obstruction and hence of clinically significant disease. Cardiac PET has the advantage from SPECT of higher spatial and temporal resolution, and a decreased radiation exposure to patients. Hybrid cardiac imaging combining SPECT or PET with CT data appears to offer superior diagnostic and prognostic information in patients with intermediate risk for CAD. A significant progress in better quantification of myocardial blood flow and coronary flow reserve has recently been seen. Also several studies have demonstrated that the combination of imaging apoptosis and matrix metalloproteinases production can help imaging vulnerable plaque and identifying the group of high-risk asymptomatic patients who will benefit most by an imaging procedure.     

Comparison Between the Performance of Quantitative Flow Ratio and Perfusion Imaging for Diagnosing Myocardial Ischemia

ObjectivesThis study compared the performance of the quantitative flow ratio (QFR) with single-photon emission computed tomography (SPECT) and positron emission tomography (PET) myocardial perfusion imaging (MPI) for the diagnosis of fractional flow reserve (FFR)−defined coronary artery disease (CAD).BackgroundQFR estimates FFR solely based on cine contrast images acquired during invasive coronary angiography (ICA). Head-to-head studies comparing QFR with noninvasive MPI are lacking.MethodsA total of 208 (624 vessels) patients underwent technetium-⁹⁹m tetrofosmin SPECT and [¹⁵O]H₂O PET imaging before ICA in conjunction with FFR measurements. ICA was obtained without using a dedicated QFR acquisition protocol, and QFR computation was attempted in all vessels interrogated by FFR (552 vessels).ResultsQFR computation succeeded in 286 (52%) vessels. QFR correlated well with invasive FFR overall (R = 0.79; p < 0.001) and in the subset of vessels with an intermediate (30% to 90%) diameter stenosis (R = 0.76; p < 0.001). Overall, per-vessel analysis demonstrated QFR to exhibit a superior sensitivity (70%) in comparison with SPECT (29%; p < 0.001), whereas it was similar to PET (75%; p = 1.000). Specificity of QFR (93%) was higher than PET (79%; p < 0.001) and not different from SPECT (96%; p = 1.000). As such, the accuracy of QFR (88%) was superior to both SPECT (82%; p = 0.010) and PET (78%; p = 0.004). Lastly, the area under the receiver operating characteristics curve of QFR, in the overall sample (0.94) and among vessels with an intermediate lesion (0.90) was higher than SPECT (0.63 and 0.61; p < 0.001 for both) and PET (0.82; p < 0.001 and 0.77; p = 0.002), respectively.ConclusionsIn this head-to-head comparative study, QFR exhibited a higher diagnostic value for detecting FFR-defined significant CAD compared with perfusion imaging by SPECT or PET.     

Tc-99m tetrofosmin myocardial SPECT perfusion imaging: comparison of rest-stress and stress-rest protocols

Aim. The purpose of this study was to evaluate the diagnostic value of Tc-99m tetrofosmin SPECT myocardial perfusion scintigraphy rest/stress and stress/rest protocols for the assessment of coronary artery disease (CAD). Methods. 65 patients underwent both rest and stress SPECT imaging in a one-day protocol and coronary angiography within 2 months before or after scintigraphy. Scintigraphic data was obtained according to two different protocols; 1) rest-stress (n=18) and 2) stress-rest (n=47). Results. Scintigraphic evidence for myocardial ischaemia was found in 36 patients (55%). The overall sensitivity to detect CAD (>50% luminal stenosis) was 94% (34/36), specificity 66% (19/24), positive predictive value 77%, negative predictive value 90%. The sensitivity to detect CAD for protocols 1 and 2 were 100% and 93%, specificity 56% and 70%, positive predictive value 69% and 81% and negative predictive value 100% and 88%, respectively. The left anterior descending coronary artery showed a sensitivity (overall, protocol 1 & 2) of 78%, 75% (3/4) and 79% (15/19) and a specificity of 71%, 64% (9/14) and 75% (21/28). The right coronary artery showed a sensitivity (overall, protocol 1 & 2) of 91%, 100% (6/6) and 88% (14/16) and a specificity of 70%, 92% (11/12) and 61% (19/31). The left circumflex coronary artery showed a sensitivity (overall, protocol 1 & 2) of 50%, 67% (2/3) and 46% (6/13) and a specificity of 94%, 100% (15/15) and 91% (31/34). Conclusion. Tc-99m tetrofosmin appears to be a valuable tool in predicting significant CAD. The sensitivity and the positive predictive value are high, making this test highly appropriate for the diagnosis of CAD. The diagnostic value of the individual coronary arteries is high to moderate. No significant differences were found between both protocols.